I'm the Villainess, So I'm Taming the Final Boss

Aileen finds out that Cedric's new fiancée, Lilia Rainworth, has received threatening letters that were signed by herself. Since she has no memory of doing so, she has her friends help her find out the truth. On the night of the ball, Aileen attends wearing the dress and accessories given to her by Claude. At the same time, Lilia appears at the demon lord's castle.